L745870

The D4R antagonist L-745, 870 (Sigma) was first dissolved in dimethyl sulfoxide (DMSO) to make a stock solution and stored at 4 °C. This stock solution was then diluted in ACSF to a final concentration of 50 nM, ensuring that the final DMSO concentration did not exceed 0.1%. These concentrations were used as they did not affect basal synaptic transmission^{33 (link)}. The D4R agonists, PD 168077 (Sigma) and Ro-10-5824 (Tocris), were both used at 0.1 µM and anisomycin (Sigma), a protein synthesis inhibitor, and KN93 (Sigma), a CaMKII inhibitor were used at a concentration of 25 µM and 1 µM respectively. PD 168077 (Sigma), Ro-10-5824 (Tocris), anisomycin and KN93 were dissolved in DMSO to make stock solutions and later were dissolved in ACSF. The NMDA antagonist, AP5 (Sigma) was dissolved in water and was used at 50 µM concentration.

PD168077 (D₄ receptor agonist), L745870 (D₄ receptor antagonist), streptozotocin (STZ) were from Sigma Co. (Sigma, St. Louis, MO). Insulin was purchased from Roche Group (Basel, Switzerland); Rabbit polyclonal antibody against Insulin receptor, cleaved caspase 3 and Histone H3 were from Cell Signaling (Beverly, MA). Antibody for proliferating cell nuclear antigen (PCNA) was from Santa Cruz. SDS-polyacrylamide gels were from Pierce (Rockford, IL). Polyvinylidene fluoride (PVDF) and protein gel apparatus were from Bio-Rad (Hercules, CA). Minimal essential medium (MEM), Dulbecco’s modified Eagle’s medium (DMEM), and fetal bovine serum (FBS) were from Gibco/Invitrogen (Carlsbad, CA); fibroblast growth factor (FGF), epidermal growth factor (EGF), phosphate buffered saline (PBS), penicillin/streptomycin, and non-essential amino acids were from Sigma Co.